RA28 1jzgte Very Strange Idle and Running issues

[77GZE]

Hey guys, just got my JZA28 on the road and yes, without fail i expected problems, but the engine has run sweet up until driving it yesterday when it started spluttering, just driving it, as if out of fuel, so i got it home and checked, Shiteloads of fuel and pumping heaps at the engine end from the surge tank.
Anyway, it was coughing and spluttering, and then would come good and then cough for a bit and then, 5 minutes later come good. But during this, it doesnt rev very well. Can rev it up but splutters:
After playing with it for hours trying to find something wrong i just started it after fixing a Pinhole vacum leak i found in a small hose, and it didnt run. I tried to start it again and it went straight up to 2500 rpm and wouldnt come down.
By this time i just threw in the towel, getting late so i came here in search for the holy grail!

Now, here is all the things i have checked.

Checked for vac leaks (fixed 1 pinhole in a vac lead)
Fuel and pumps
Spark plugs arnt gummy or even very old looking
All the electrical connections i could get my grubby hands on.
Currently have dissconnected the battery for 10 minutes because thats what the supra forums guys said to do to reset it.

Any help much appriciated.
Steve

[77GZE]

Ok breakthrough, sort of, Resetting the ecu left me back with problem number one,
The car will run but rough as.
Alot worse since a bloke told me to check intake manifold gasket, and lean on the manifold see if the idle changes. so im leaning toward a manifold gasket.
Would this make for a rough low idle and missing and what not?

[The Real Roadrunner]

is the ISCV working properly? has it got power?

sounds like what one of my customers cars did, would run sweet sometimes and shit at others, turned out it was the capacitors in the ecu, what model is yours? his was an A70 ecu and apparently its a common problem.

manifold gasket would make it rev its tits off, thats why i suspect it may be a gummy ISCV aswell as the capacitor problem as his did both at the same time.

cheers
linden

[unclewal]

Ok breakthrough, sort of, Resetting the ecu left me back with problem number one,
The car will run but rough as.
Alot worse since a bloke told me to check intake manifold gasket, and lean on the manifold see if the idle changes. so im leaning toward a manifold gasket.
Would this make for a rough low idle and missing and what not?

MAP sensor maybe?

[brett_celicacoupe]

yep,

sounds like the line to the map sensor is off or damaged.

and if you didnt power the ISCV then it will be open from when the engine last run. when the engine stops they open fully (clicking noise). for memory its a 6 pin plug like the 1g/7m, then the 2 inner pins should have +12V.

[The Real Roadrunner]

MAP sensor maybe?

yeah forgot about that one, this man speaketh the truth (why do i always assume the worst )

cheers
linden

[SillyCarS]

brett, roadrunner. great info guys

[jeffro ra28]

so an ISCV is a???

[brett_celicacoupe]

idle speed control valve

[77GZE]

Fixed guys! turns out the ecu had had the pork chop even tho the capacitors had been replaced, got new ecu and fixed it!